


Dark Chemistry

by lezbekat



Category: Once Upon a Time (TV)
Genre: Alternate Universe - College/University, F/F
Language: English
Status: Completed
Published: 2019-10-05
Updated: 2019-10-05
Packaged: 2020-11-24 00:55:43
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,147
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20898983
Author URL: https://archiveofourown.org/users/lezbekat/pseuds/lezbekat
Summary: Emma Swan has just started her last semester at college. She needs to pick a science class to complete her mandatory credits and decides on chemistry with Dr. Regina Mills based on reviews of her class online. But when your eyes convey your every emotion by changing colors, things can get a bit complicated.College AU One Shot.





	Dark Chemistry

Everyone knows that the eyes are the window to the soul. And of course, they have to go around revealing everything you're feeling. For most people, it's pretty easy to control their emotions and walk around with varying shades of grey, yellow, and purple orbs. But for Emma, she's an open book. She's never been great at concealing her emotions. It's gotten her into quite a bit of trouble when she was younger. She could never fake a happy yellow nor hide her red anger.

Now, she was finally about to graduate college with a degree in literature and a minor in psychology. She didn't have to try to hide her emotions as most of the time she truly was happy. She had left mostly general classes for her last semester, not wanting to have to work too hard. She still needed a science course but couldn't decide on which one. After a search on a professor rating site, she decided to take Chemistry 101 with Dr. Regina Mills. Yes, the only open class right now was a Monday, Wednesday, Friday course and a Friday evening lab but it was her best option. Emma wasn't the biggest fan of the sciences. Fortunately, the reviews had said her class was easy to pass because she was new. As long as you showed up to every lecture you would be fine. And that was pretty easy considering she was attractive. Granted, almost every single female professor had reviews that mentioned how attractive they were because college guys are the worst so Emma didn't think much of that part.

She wasn't quite prepared when she walked into Dr. Mills class for the first time. Emma chose a seat in the last row, closest to the door. She didn't like being near other people nor too far from an exit, if possible. When Regina walked into the room and greeted the class with a warm smile, Emma was instantly grateful she chose the spot she did. Regina was gorgeous. Drop dead beautiful. Emma could sense her eyes darkening as she started at the petite brunette professor.

For the next few weeks, Emma diligently took notes, completed all her assignments, and even sort of enjoyed the lab work, although it did cut into her Friday night partying time. There were an odd number of students in her lab so Emma was able to work alone, which she preferred. She took the work bench furthest in the back even though it was also the furthest from the door. The other 6 students filled in the closer work benches. From the back of the room Emma could discreetly watch her professor without her seeing just how dark her eyes became when she was around.

\-------------------

Regina loves chemistry. She loves teaching. But small children don't learn chemistry in school and high schoolers are the worst so Regina decided becoming a college professor would be the best option for her. She took the job at a small liberal arts college in Maine. So far, her first semester went really well. She didn't have to fail any students and they all respected her. She could tell that most of the students in the class didn't really care about chemistry and were only there to satisfy their science requirements but that was fine. She was still looking forward to this new semester. Another chance to impart knowledge and maybe inspire someone to actually enjoy the amazing world of molecules.

When Regina entered the small lecture room for the first time this semester, she quickly scanned over her students to get a feel for how the course will play out. Most of the students had varying shades of yellow dancing in their eyes. Some were mostly grey already. Very few had any hint of speckled brown interest. Her eyes then found the blonde sitting in the back near the door. She couldn't quite see her eyes as the girl was focused on scribbling something in her notebook. Regina could tell her own yellow eyes were developing black specks so she quickly looked away and began the class. She hoped this blonde woman would be in one of her labs. Come Friday evening Regina was pleasantly surprised to see that the tall blonde was, in fact, in her lab. Her Friday evening lab, nonetheless. With only seven students since college kids would rather party on Friday night than take a three hour long chemistry lab. Regina soon learned that the blonde’s name was Emma. Emma Swan. A senior about to graduate. Regina had suggested that Emma join one of the other pairs to work in a group of three but Emma insisted she would be fine and that she worked better on her own. The girl kept her gaze down and Regina was unable to get a read off her. She would just have to pay more attention.

\------------‐-----------

It was nearing the end of the course now. It was the last week before finals and Regina was lecturing about pH and how acids and bases react. Boring material, but necessary to present in class and would most definitely be on the final. She spent most of the lecture time at the board, writing out chemical formulas and demonstrating the calculations for determining the molarity of the acid. Yes, boring, but not to Regina. Her eyes were a bright sunshine yellow with a brown center, not unlike a sunflower. She could go on for hours about chemical interactions and the elegant way mathematics brings actual values to a visual reaction.

She looked up at her class and sighed. Every single student, if they were even awake, showed the tell tale sign of boredom --- grey eyes. She's used to this. Most of the students in this class don't really care, they just need it to finish their mandatory science credits. Plus, the material isn't that hard, mostly just memorizing chemical structures and basic mathematical formulas. Closer to the holidays and breaks the students eyes were mostly shades of happy yellow and playful orange. Occasionally she'd see sad blue or angry red eyes staring at the ceiling or their notebooks. Or the magenta eyes of two lovers paying attention to only each other. On rare occasions she would see a pair of bright yellow eyes speckled with brown from the few who were genuinely interested in the subject. She had even seen a few dark grey and nearing black eyes from horned up college boys and the occasional girl. But today, every student had glossed over shades of grey. Every. Single. One. Except...wait. Regina pauses as she locks eyes with the blonde student sitting in the last row, closest to the door. She averts her gaze quickly but not before Regina let's out a small gasp and her eyes whiten in surprise. Emma's eyes are black. A deep, obsidian black. Darker than any Regina has ever seen staring back at her. The blonde quickly gathered her things and bolts out the door.   
The other students, previously on the verge of falling asleep, look up to see what was going on. Their eyes lighten, flecks of orange and brown starting to populate. Regina quickly regains her composure, clears her throat, and dismisses the class. She decided she had enough of acid-base chemistry for today. Besides, she could tell her eyes were starting to become speckled with black now too. She needed to regain herself before lab that afternoon. She knew Emma would be there. Sitting alone at the furthest bench. Today, however, Regina would not allow Emma to complete the lab on her own. No, today Regina would be her lab partner. She would insist it was too dangerous to do alone. It wasn't; just a simple phenolphthalein titration of acetic acid with sodium hydroxide. But she just had to get another look at this girl. She wanted to confirm what she saw earlier. She needed to. Because, if she was being completely honest with herself, she found Emma attractive. From the first day of class when the tall blonde took a seat in the back Regina knew there was something intriguing about this woman.

Regina could not wait for lab this evening. She walked into the small space and began to set up for the evening. She placed a flask, buret and stopcock, buret stand, and glass jars of the solutions needed at each work bench. Then, she turned her attention to the board and began to write the chemical equations and calculations the students would need for this experiment. As she was writing, her students started to file in. Lab didn't start for another fifteen minutes but that didn't stop Regina from wondering if Emma would even show up as the other six students were already there. Her worry was short lived as Emma entered the lab at 5:53, her eyes cast down as she quickly made her way to the back work bench. Regina smirked a bit; she knew she really had seen Emma's eyes turn as black as ink.

Since everyone was already there, Regina decided to start her introduction to the experiment. The faster she could get that out of the way, the faster she could make her way to the back towards Emma. It only took twenty five minutes for her to explain the lab and get everyone started. Once she was satisfied that the other pairs had their equipment set up properly and were donning the right protective gear, Regina walked back towards Emma's bench. As she approached, Regina noticed that Emma was concentrating hard on filling her buret with sodium hydroxide. She couldn't quite see her eyes as the goggles Emma was wearing were slightly fogged over.

"Careful Emma, you don’t want to spill this on you. It leaves quite the burn." Regina said softly.   
Emma jumped slightly and did in fact manage to splash a few drops onto her lab coat. Regina chuckled quietly.   
"Sorry Dr. Mills, I'm usually much more steady handed." Emma said after placing the buret securely in its stand.   
"No need to apologize. This lab is a bit dangerous. I would feel more comfortable if I worked as your partner today"  
Emma visibly gulped. Boy did Regina hate those foggy goggles now. Regina reached into her lab coat pocket and removed a pair of safety glasses. She held them out towards Emma.  
"Here, these will make it easier to see what you're doing so we don't have a bigger spill."   
Emma took the glasses from Regina and replaced the giant goggles on her face. Regina smiled; her coy plan to see Emma's eyes was going to work. But Emma didn't look up. She kept her eyes down and focused on the task in front of her. After a few moments, one of the other students called Regina over for help. They had accidentally over titrated and their solution turned a very bright shade of magenta instead of the barely-there hint of pink it should be. Regina quickly pointed them to the vial of acid and instructed them to add more, recording the exact amount in their notebooks. It didn't take long for the pair to get it right. The other two pairs had also just finished their titrations and were beginning to clean up their stations. Regina glanced at Emma to see if she was close to finishing as well. She could barely contain her grin nor stop her eyes from turning dark grey with flecks of orange when she noticed that Emma too, had over titrated. Regina helped the students who had finished clean up so they could leave early. Getting done by 7:30 on a Friday night was always a blessing to the ever party ready college kids.

As the other students started to leave, Regina made her way back to Emma's bench. Emma was quietly muttering to herself as she tried to measure more acid with shaking hands.   
"Let me, I am your partner for the day, aren't I?" Regina said, as she took the jar of acid from Emma's shaking hands, brushing her fingers over the blonde's. Emma glanced up briefly and Regina smirked as she noticed the black and white marbling of Emma's eyes. Regina took her time pouring the acid into a graduated cylinder, recording the exact amount in Emma's notebook, and then added it to the bright pink flask. The solution immediately turned colorless once again.

"There, all set. It may be cheating if I tell you this, but it should only take about 5 more milliliters to reach the point of neutrality. Be careful when you get close to that."   
Of course, Regina knew it would actually take 7.3 mills to reach the equilibration point but she was hoping it would make Emma go extra slow for just that slight bit longer. And it had worked. Emma added 4 milliliters of base quickly. Then, she slowed down the rate to a mere few drops every second. As she approached 5 mills, Emma added the base drop by drop. She stared at the flask in front of her, waiting for that slight pink color to appear. Regina stared at Emma, unable to stop her eyes from darkening while she watched the woman bite her lip as she concentrated. Finally, at 7.3 mills the solution took on the faint pink hue. Emma nearly jumped up, her eyes shining bright yellow with spots of brown and white at the joy of finally succeeding. She looked at Regina and immediately her eyes darkened. She looked away just as fast and scribbled down the volume of base used in her notebook. She then began to clean up her station, taking care to dump the solutions into the correct waste containers. Regina gathered the now empty glassware and placed them in the glass bin to be loaded in the dish washer. She then went back to the bench to put away the buret stand. The students had put their stands back on the bottom shelf, leaving Regina with no choice but to stretch as far as she could on her tippy toes to try and place the stand on the top shelf. Emma quickly came over and easily slid the stand onto the shelf, brushing against Regina as she did. With her eyes still cast down, Emma turned to Regina.  
"Thank you for your help today, Dr. Mills. I don't know why I had such a hard time with this experiment. I'm usually the first to finish." She fidgeted with the safety glasses in her hands that Regina had loaned her as she spoke.   
"Its not a problem, Emma. This one can be a bit tricky if you're distracted in even the slightest bit." Regina tried to look Emma in the eyes, her own a deep black now with hints of orange. But Emma refused to look up. She continued to fidget with the glasses. So Regina did the only thing she could think of. She gently grabbed the glasses in Emma's hands, leaving her hands to linger on the blonde's. Emma looked up suddenly, her eyes flashing purple and white before darkening to black. Regina smiled.  
"I knew that's what I saw earlier." She leaned in and softly kissed Emma's lips. Just a quick, gentle kiss. She pulled back and saw white flash in Emma's eyes before returning to the deep black they were.

This time, it was Emma who leaned in. She kissed Regina deeply. Passionately. She tugged her hands from Regina's grasp, letting the glasses drop to the floor. She placed one around her waist and the other on the back of her neck, pulling her closer. When they finally broke for air, both women had eyes darker than night. Regina turned slightly to check that the door to the lab was closed. She knew no one else would be in this wing at this time on a Friday but still, some sense of privacy would be best. She turned back to Emma and smiled devilishly. She pushed Emma back against the wall of cabinets and kissed her again. This time she was a bit rougher, more intense. She let her hands roam the woman’s body. And Emma's roamed as well.

After a few minutes, Emma pushed back on Regina without breaking contact. She grabbed her at the waist and lifted her on to the nearest lab bench. She continued kissing Regina, slowly trailing her lips down her olive toned neck then along the deep-v collar of her navy blouse. Regina moved her hands to unbutton her shirt, exposing her toned stomach to the blonde. Emma broke contact for just a moment to take in the view. A lacy black bra against smooth, tanned skin. She looked at Regina's eyes, they were still a deep black, her mouth slightly agape as she stared back at Emma. Emma lightly scraped her fingers down Regina's torso and stopped at the button of her dark denim jeans. She expertly popped the button open and worked the zipper down. Regina lifted her hips slightly to aid in the removal of her pants. Emma slipped her fingers under the delicate lace of Regina's panties. She slid one digit into the sick folds, relishing in the wetness. Regina let out slow moan as Emma slowly pushed her finger into the brunette. The blonde gently thrust her finger in and out at an achingly slow pace. Regina moaned again, louder and longer this time. She began to rock her hips slightly faster than Emma's pace, trying to encourage her student to move faster. Emma got the message and picked up her speed. She added another finger and Regina gasped then bit down on her lip. As Emma continued to move inside Regina, she used her other hand to feel Regina's smooth skin. She slid her free hand up her torso and gently teased at Regina's pert nipple through her bra. Regina moaned again and her hips buckled against Emma's hand. She wrapped her arms around Emma's neck and pulled her closer. Emma took Regina's lips between her teeth and pulled gently then kissed her tenderly. Regina gasped and hoarsely whispered "Don't stop, Emma. I'm so close."  
Emma maneuvered her thumb to brush against Regina's swollen clit with every thrust. She increased her speed and force as Regina rocked hard against her, muffled moans escaping her throat. She felt Regina's muscles tighten around her fingers and then release rapidly. She slowed her pace then smoothly removed her fingers when Regina stopped rocking her hips and let her arms loosen around Emma's neck. They stayed there for a moment, Regina hanging onto Emma and Emma holding Regina tightly. They looked at each other once more and saw deep magenta rings around the black in their eyes.   
"Wow." Emma said quietly, "who knew I would actually enjoy a Friday night lab."

**Author's Note:**

> Thank you for reading! I hope you enjoyed it. This is my first time posting to AO3 and the first story I've written in ages. Comments are always welcome!


End file.
